Can someone please tell me who should I raise between alexander and medusa for farming purposes?
Medusa for sure. 20% NP gauge + a little NP gain up in skill 3 help her release NP faster. If you don’t mind, I advise to roll 4* Astolfo
For pure farming, start with Medusa, as she is F2P 20% charge of self NP.
It helps a lot, plus Mosntruous Strenght carries some punch.
Alexander is still good, being quick support (post-ST quest) he can support your Medusa and many others. Instant stars post NP is nice, also.